Bar Charts, Histograms, and Scatterplots

Descriptive statistics

Techniques to describe or summarize data.

Inferential statistics

Techniques to draw conclusions or make inferences about a population based on information obtained from a sample.

Frequency distribution table

Shows how data are partitioned among several categories by listing the categories along with the number (frequency) of data values in each.

Bar graph

A graph that uses bars of equal width to show frequencies of categories of categorical (or nominal) data.

Histogram

A graph consisting of bars of equal width drawn adjacent to each other representing the frequency distribution of quantitative data.

Relative frequency

Class frequency divided by total frequency.

Normal distribution

A bell-shaped, symmetrical distribution of data.

Right-skewed distribution

An asymmetrical distribution with extreme high values.

Left-skewed distribution

An asymmetrical distribution with extreme low values.

Bimodal distribution

A distribution with two peaks, indicating a possible division in a population.

Scatterplot

A graph illustrating the relationship between two quantitative variables.

R Function for Barplots

barplot().

R Function for Histograms

hist().